Abstract: To improve the quality of the demodulated signal without altering the form in which an AM radio wave is transmitted, the received amplitude-modulated signal is converted to a single-sideband signal, and the information signal demodulated from the phase term of this converted single-sideband signal.

Abstract: To improve the quality of the demodulated signal without altering the form in which an AM radio wave is transmitted, the received amplitude-modulated signal is converted to a single-sideband signal, and the information signal demodulated from the phase term of this converted single-sideband signal.

Abstract: The invention addresses itself to the task of providing a medium-frequency stereo broadcast receiving circuit that does not require any alteration of the radio wave format used in the medium-frequency stereo broadcast system that has become the de facto standard, and that receives transmitted broadcast waves and removes, in the course of the demodulation process, disturbance that has affected the signal during its propagation, thereby improving the audio quality of the demodulated signal and obtaining the full potential of the stereo effect. To achieve this, the received medium-frequency stereo broadcast wave is converted to a single-sideband signal, and the sum signal (L+R) is demodulated from the phase term of this converted single-sideband signal. The difference signal (L−R) is demodulated from the phase term of the received medium-frequency stereo broadcast wave and from the demodulated sum signal output.

Abstract: This invention addresses itself to the task of securing excellent narrowband transmission quality when transmitting audio signals such as voice and music, or various kinds of multimedia signal, by means of unidirectional or broadcast communication systems. Excellent demodulation characteristics are obtained by reducing the required transmission bandwidth by using SSB modulation technology, and by performing RZ SSB demodulation at the receiving side. The sideband and the carrier component are transmitted at a sufficient distance from one another in the frequency domain so that even if frequency stability in the transmitting and receiving circuits is not very high, there is little likelihood of quality deterioration due to frequency instability, and so that the receiving circuit is easier to implement, since less sharply selective bandpass filters are required.